XRA00 Datasheet, PDF (28/40 Pages) STMicroelectronics – UHF, EPCglobal, Contactless Memory IC 96 bit ePC with Inventory and Kill Function

XRA00
PingID
The PingID command is a Basic command that
gives rise to a response from the XRA00.
When the command is sent, the XRA00 will re-
spond if the data sent by the Reader in the [VAL-
UE] field matches the data in the XRA00's internal
memory starting at the location specified by the
[PTR] field. Data in the [VALUE] field is compared
to the XRA00 memory, from the lowest to the high-
est memory address. XRA00 devices whose data
matches all of the bits in the [VALUE] field will re-
ply to the Reader. XRA00 devices whose data
does not match or that fail a parity test on any of
the parity bits will not modulate.
The PingID command is used as part of a multi-
XRA00 anti-collision algorithm described in detail
hereafter.
XRA00 devices that match the data sent by the
Reader respond with 8 address bits, from a point
designated by two parameters supplied by the
Reader, in increasing address order.
Each XRA00 response is placed in one of 8 Bin
Response Windows delineated by BIN pulses sent
by the Reader.
Example of a PingID Command. A Reader is-
sues a PingID command containing the following
data:
[CMD] = 00001000_b (PingID)
[PTR] =
00000111_b (0x07)
[LEN] =
00001001_b (0x09)
[VALUE] = 000101101_b (0x2D)
The XRA00 devices will attempt to check 9 bits of
their address data, starting at bit 7 against the data
specified in the [VALUE] field.
In the example shown in Table 10., the underlined
bits in the XRA00 ID code are compared with the
[VALUE] data sent by the Reader. Bits shown in
Italic are modulated and returned to the Reader
during one of the Bin Response Windows. The
lowest 3 bits of the response determine the re-
sponse bin number.
Table 10. Example of PingID Operation
XRA00 ID Code/Bit Position
XRA00 responds to
PingID command
Towards Highest
Address Bit
Lowest Address Bit
Bit Number
...321098765432109876543210
-
XRA00 1 ID
...010001000001011011101010_b
YES
XRA00 2 ID
...100111100001001010010010_b
NO
(bit 10 does not match)
XRA00 3 ID
...111101010001011011110110_b
YES
XRA00 4 ID
...101100000001011011110111_b
YES
Bin for
response
-
Bin 4 (100_b)
-
Bin 5 (101_b)
Bin 0 (000_b)
8-Bit
response
MSB LSB
-
01000100_b
-
11110101_b
10110000_b
Figure 30. PingID Answer Frame Structure for XRA00 3
Bin 5
(101)
Lowest XRA00
address
10101111 (pattern reflects order of transmission)
Tag Data (8 bits)
Bin 6
(110)
Highest XRA00
address
ai10769
PingID Answer Frame
The PingID command is used in the anti-collision
algorithm. This command requires that the XRA00
devices that match the data sent by the Reader re-
ply with 8 modulated data bits in one of 8 Bin Re-
28/40